What kinds of test is suitable for low volume PCB order?

I've ordered fabrication and assembly of small PCB batches (100pcs) a couple of times already. Each time the factory asked me if I want to do test on the PCB. But I don’t what to do about it. And I test them by myself. Then, the result of the testing is unacceptable with 15% soldering problems. So bad. I think I will ask the supplier to test them before delivery.

PCB Assembly, PCB Testing
November 16, 2023

For the order with large volumes, a certified factory usually tests the bulk for you without informing you. For low-volume PCB, we suggest

Flying Probe (basically an automated way of contacting pins and checking if the resistance meets expected values). This also comes relatively cheap since the programs can be created from netlists which have to be specified by the customer.
In-Circuit-Tests: This is probably the most extensive test method we use (and also the most expensive). Basically, we build an adapter that will host the DUT and contacts the various test points. Using integrated Boundary Scan techniques and stimulating digital and analog signals nearly every mode of testing is possible.
Boundary Scan: The Flying Probe can mainly contact test points or larger points such as resistors, … if there is no available point to touch it on the PCB, the Flying Probe is of no use. To test Inter-IC connections we mainly rely on Boundary Scan Tests if the Controller supports these. But they have their limits as well. Also, programs can be “written” automatically but need to be adapted.

These can basically cover the requirements. Still, 100% testing is not possible, but it is a good idea to manage the quality and your supplier.

#PCB Assembly #PCB Testing

Oliver Smith

Oliver is an experienced electronics engineer skilled in PCB design, analog circuits, embedded systems, and prototyping. His deep knowledge spans schematic capture, firmware coding, simulation, layout, testing, and troubleshooting. Oliver excels at taking projects from concept to mass production using his electrical design talents and mechanical aptitude.

Oliver Smith

What Others Are Asking

Is PCB testing of all nets after assembly required?

That is my first time asking an assembly house to produce 200 units of a PCB (and not the usual 3 or 5 PCBs). The assembly house came back to me saying that the testability of the board was bad and that they need to have 1.2 mm pads on the bottom side of the PBC for all nets… They require such large pads because beds of nails are a much more economical option than flying probe for 200-400 units since they can do it in-house. Is adding 1.2 mm pad on ALL nets common practice for PCB?

Oliver Smith October 26, 2023

How can I remove tenting on vias after assembly for debugging?

I have two BGA parts on a PCB, with a 32 bit wide bus with a few control lines and a clock line connecting them. Almost all of these traces are only on internal layers. There looks like a signal integrity problem on the bus. The good news is that the board only has parts on one side, and all the vias are through-all. Can anyone suggest good ways to remove the tenting over the vias so they could be probed with an oscilloscope, or at least be able to solder 30 gauge wire to them?

Oliver Smith December 1, 2023